Gleam club sets beacons to expire no sooner than the gleam club subsription.
Buying 1 month GC means any beacon with fuel less than 1 month will ‘be fueled’ by GC up to 1 month; any beacon can still be fueled higher than the gleamclub duration (so you can pre-fuel beacons as your GC is running low if you dont intend to renew), and in this case the beacon already had more fuel than GC would provide, so GC has no effect on the beacon right now.